Java 多线程环境下函数失效的线程安全测试和验证方法？

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class Fibonacci {

    public static int calculate(int n) {
        if (n == 0) {
            return 0;
        } else if (n == 1) {
            return 1;
        } else {
            return calculate(n - 1) + calculate(n - 2);
        }
    }

    public static void main(String[] args) {
        // 单元测试
        ExecutorService executor = Executors.newFixedThreadPool(4);
        for (int i = 0; i < 100; i++) {
            executor.submit(() -> calculate(i));
        }
        executor.shutdown();

        // 锁机制验证
        Object lock = new Object();
        ExecutorService lockExecutor = Executors.newFixedThreadPool(4);
        for (int i = 0; i < 100; i++) {
            lockExecutor.submit(() -> {
                synchronized (lock) {
                    calculate(i);
                }
            });
        }
        lockExecutor.shutdown();

        // 不可变对象验证
        for (int i = 0; i < 100; i++) {
            // 创建不可变的fibonacci数组
            int[] fibonacci = new int[i + 1];
            fibonacci[0] = 0;
            fibonacci[1] = 1;
            for (int j = 2; j <= i; j++) {
                fibonacci[j] = fibonacci[j - 1] + fibonacci[j - 2];
            }

            // 使用多线程同时访问fibonacci数组
            ExecutorService immutableExecutor = Executors.newFixedThreadPool(4);
            for (int j = 0; j < 100; j++) {
                immutableExecutor.submit(() -> {
                    int result = fibonacci[j];
                    // 检查结果是否与预期的一致
                });
            }
            immutableExecutor.shutdown();
        }
    }
}